The stem of a bicycle can be made from alloy, carbon or titanium.
Most bicycle handle grips are made of black rubber. One can separately purchase foam slide on grips or Nitrile Foam grips is one has a sensitivity to black rubber.
The bike rack, and the seat material actually has little cyclist images in it.
a booster seat is made out of plastic and a soft kind of material for comfort why did you want to know
if its a one seat bike no, not unless you want to crash
Tubular steel or carbon fibre.
BMX bike ramps are usually made out of material such as chrome or aluminum. They have to be durable enough for multiple people to use them at the same time.
there will be no rails on the bottom of the seat.
Seat height is the seat And overall height is to the tallest point on the bike, like the bars
On the bike under the seat there is a leveler that can make it move up and down you unlock it then adjust it then lock it
seat ajustment.
The cushion should be made of a breathable material so it can transfer heat easily. The seat itself is sometimes an exercise bicycle seat. Many are made of a soft leather.
Yes on this model of excercise bike the seat is fully adjustable to a variety of different vertical heights.
Multisports-CardioCycle-4050R-Recumbent-Bike does have arrangement to adjust the angle and height of the seat.